The custom or condition of having only one mate in an intimate relationship, of being dedicated to a single partner.

Monogamy is a traditional ideal in various societies, yet many people in these societies are not monogamous.

Cheating (being involved with someone else, with secrecy and deception) is a destructive way to be nonmonogamous. On the other hand, swinging and polyamory (types of responsible nonmonogamy based on the knowledge and consent of everyone involved) are viable choices for some people.